A torque converter incorporated in an automatic transmission to transmit an engine power output to a speed change mechanism comprises a pump adapted to be rotated integrally with a crankshaft of an engine, a turbine disposed opposed to the pump and adapted to be driven by the pump through fluid, and a stator disposed between the pump and the turbine and adapted to perform a torque amplifying function. The pump, the turbine and the stator define a torus (a doughnut-shaped fluid working section for causing fluid to circulate therearound).
In order to improve engine fuel economy, the torque converter may further comprise a lockup clutch adapted to be engaged so as to directly couple the pump and the turbine, except when the torque amplifying function is utilized, such as during vehicle starting, and when it is necessary to permit a relative rotation between the pump and the turbine, such as during speed changing. In this case, a lockup damper is provided on an input or output side of the lockup clutch to absorb shock during engagement of the lockup clutch.
As the torque converter having the above structure, there is a type disclosed in the following PTL 1. In this torque converter, a wet multi-pate lockup clutch is disposed between a front cover defining a surface of a casing on the side of an engine and a turbine provided within the casing, and a lockup damper having a damper body and a plurality of damper springs is disposed on an outer peripheral side with respect to the lockup clutch, in such a manner that arrangement positions of the lockup clutch and the lockup damper axially overlap with each other.